# Entropy and area.

@article{Srednicki1993EntropyAA, title={Entropy and area.}, author={Srednicki}, journal={Physical review letters}, year={1993}, volume={71 5}, pages={ 666-669 } }

The ground-state density matrix for a massless free field is traced over the degrees of freedom residing inside an imaginary sphere; the resulting entropy is shown to be proportional to the area (and not the volume) of the sphere. Possible connections with the physics of black holes are discussed.

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